Characteristics of soil organic carbon at 38°N ecological transect of Hebei Province Evaluation of rural residential land consolidation potential using entropy weight extension model-A case study of Taihang Mountain piedmont plain in Hebei Province Spatial and temporal variations in optimum sowing date of winter wheat in Shijiazhuang City Operation and demonstration of precision planting in Luancheng County Species Diversity and Spatial Heterogeneity of Plant Communities in Piedmont Plain of South Slope of Tianshan Mountains